AMPHIBIANS AND REPTILES: COMMON EUROPEAN VIPER, VIVIPAROUS LIZARD, COMMON FROG, FIRE SALAMANDER, COMMON TOAD

Common European viper (pl żmija zygzakowata)

There are four species of snakes living in Poland and among them there’s the common European viper, which is the only Polish venomous snake. How to distinguish it among other snakes? Well, all you have to do is to look in its eyes. The pupils of the common European viper are narrow and vertical. Its head is heart-shaped while the heads of other Polish snakes are more diamond-shaped. Most of the vipers have characteristic zigzag on their backs, known as the band of Cain, although not all of them, so you can’t be sure that the snake isn’t a common European viper even if it doesn’t have a zigzag. The common European viper may have various coloration – there are brown, grey, bright and black specimens and sometimes, over the course of time, the vipers change their colours.

The common European vipers are ovoviviparous. Every two or three years the females give birth to few or few dozens of young. The vipers are still in egg coats and have to get out of them on their own. The young vipers have length of few dozen centimetres. They spend winter in lairs nearby their mother’s . The lairs have to be deep enough, so the vipers wouldn’t freeze during winter, and secure from spring’s floods. The young male vipers leave their lairs in March if there is no snow nor cold in spring, while the young females wait until April. The common European vipers are cold-blooded amphibians so they have to warm their bodies properly by staying in the sunlight for extended periods of time in order to be active. In spring, from April till the end of May, the males look for females to reproduce. Once the males find an adequate female they begin the rivalry to secure their chance of conceiving an offspring. The rivalry takes form of the mating dance, during which the males try to push their rival’s head to the ground. What is important here is that the vipers never use their venom during the mating dance.

The common European viper can reach the length of 70-80 centimetres. At first it preys on insects, slugs and small amphibians, but as it grows it attacks bigger animals, such as mice, lizards, hatchlings of birds and even moles. The vipers eliminate many animals that humans consider pests. Every once in a while the vipers shed their skins as they inhibit their growth. Just like other snakes, the common European vipers do not bite pieces off its prey, but swallow it whole. They are capable of swallowing animals that are bigger than the diameter of their jaws thanks to their flexible bones of viscerocranium (face skeleton). However, before the snake can swallow its prey it has to hunt it. The vipers use their forked tongues in order to locate their victims, as their tongues can sense both the taste and the smell of their prey. Then the vipers bite with their fangs and inject their venom, which in short period of time incapacitates and kills the prey. The venom of the snakes is also used in defence, however, many animals are adapted to hunt the vipers without getting bitten. The enemies of the amphibian include birds of prey, storks, corvidae, boars and, in extreme cases, bears. However, the main threat to the vipers are people, who kill them in fear of their venom, despite the fact that the common European viper is under legal protection as a species.

The vipers are not as dangerous to human as some people think. They tend to run away from people and never chase them. Also, they are incapable of biting people who wear proper shoes, even if they are stood upon. The venom of the viper is designed to kill small organisms, which is why it is only dangerous to children and people who are allergic to it. What is more, not every bite of the viper injects venom into its victim. Some bites are ‘dry’ – it happens when the viper has already used its venom for other purposes. Still, you shouldn’t neglect any bites and in case of such you should contact your doctor as soon as possible.

Viviparous lizards (pl jaszczurka żyworodna)

The viviparous lizards are the most common reptiles living in the Tatra mountains. They live below the height of 1700 meters above the sea level and they are relatively small – the maximum length of their bodies is 15-16 centimetres. Like other reptiles the lizards are cold-blooded and need to stay on sun for long periods of time to rise the temperature of their bodies. They are often seen lying on stones or trunks of trees, as there are always lots of potential hide-outs available for them in such places.

The lizards start to reproduce when they are at least 3 years old. The mating happens in May and June, and in August and September the females lay their eggs with already developed offspring. In October the lizards start to hibernate deep in their lairs, where they stay until February.

Despite their name the viviparous lizards are not actually viviparous, but ovoviparous. The hatchlings are born still in eggs which they leave only after the female gives birth to them. The hatchlings have a special tooth at the top of their mouths which helps them get out of the eggs. The hatchlings are very small, their bodies are about 4 centimetres long, and there may even be more than ten of them in one birth.

The viviparous lizards feed on insects (especially on lucusts), earthworms, spiders, slugs and other invertebrate animals small enough to fit in their mouths. They also shake their prey to immobilise it before swallowing.

The enemies of the viviparous lizards include hedgehogs, birds of prey and other predators. Their usual means of defence is running away from the danger. When pulled by predators, lizards shed their tails in response. The severed tail continues to wiggle for about 30 minutes, which sometimes occupies the predator while the lizard gets its chance to escape. Their tails grow back after some time, although smaller. Sometimes the lizards escape to water where they bury themselves in silt in order wait out the danger.

As all the reptiles in Poland the viviparous lizards are under legal protection. If you see one in your garden you should be glad, as they are excellent defenders of your plants against voracious slugs and insects.

Common frog (pl żaba trawna)

The common frog is the most numerous anuran species living in the Tatra mountains. It is not as big as the common toad, but still quite big for a frog as the females, which are bigger than the males, may even reach the length of 11 centimetres. During the mating it is the females that carry the males to water on their backs.

The common frogs have camouflage colouring – they are brownish with brighter stripes on their backs and legs, as they are pretty much defenceless against the frog-eating predators. Their skin is smooth and lacks the venom glands that protect the toads and salamanders. They are considered a delicacy by otters and most of carnivorous animals, occasionally including even wolves. Fortunately, when the otters hunt the frogs they leave their spawn intact because the otters don’t like it. Still, the worst enemies of the frogs are not the otters nor other predators, but the cars. Every year whole masses of them die when they try to cross the roads to hop into their water tanks.

During summer the common frogs are often seen even at the mountaintops above the height of 2000 meters above the sea level. They also reproduce above the upper border of forests. The common frogs hunt insects, slugs, spiders and every other swallowable animal, including smaller frogs. That is why the frogs are our allies and should be most welcomed in our gardens as they eliminate all of the potential pests.

The frogs living in places that are lower and warmer start reproducing in March while the ones living in Dolina Pięciu Stawów Polskich or on Gąsienicowa Polana wait until June. It is a similar case with the metamorphosis of young polliwogs into frogs. In warmer locations the polliwogs grow their legs and lose their tales during summer, while the ones living higher do that during fall. There has even been some cases of polliwogs hibernating through winter and going through the metamorphosis in spring of the following year. The spawn of frogs is laid in form of a jelly that contains from few hundred to few thousand of eggs.

The adult common frogs hibernate through winter hidden in silt or under the rocks of brooks and water tanks.

Fire salamander (pl Salamandra plamista or joscur in local dialect of Podhale)

Although the fire salamanders resemble lizards they are in fact not reptiles but amphibians. Compared to the other Polish amphibians the fire salamanders are very unique. The mating of the fire salamanders happens not in water, like the mating of the toads, frogs and newts, but on land. Salamanders lay their eggs with already developed offspring in brooks and creeks. The larvae of the salamanders live in water until they mature. Once they become adults they transfer to land. Unlike their spawn the adult salamanders are not good swimmers. Both the spawn and the adult salamanders are predatory. Since they are slow and clumsy so is their prey – the salamanders hunt slugs, earthworms and insects. They spend winters in hideouts under rocks and in rotting trunks of trees.

The fire salamanders defend themselves with numerous venom glands on their skin and parotoid glands, which are external skin glands on the backs of salamanders’ heads. Once the salamander is attacked its parotoid glands secrete a strong toxin – samandarin. The fire salamanders warn the predators with their bright colouring – they are black with numerous yellow and orange spots.

The fire salamanders are generally nocturnal, but sometimes they are seen active during day when it rains. People used to believe that the salamanders are fire-resilient, which is why they became the symbol of artillerymen. They are also the symbol of the Gorce National Park as the chamois are the symbol of the Tatra National Park. Like other Polish amphibians the salamanders are currently under legal protection.

Common toad (pl ropucha szara)

The common toad is the biggest Polish amphibian. The females are bigger than the males and they can reach the length of 15 centimetres.

During summer the common toads look for the water tanks. The females carry the males to water on their backs and slowly lay their eggs in two parallel lines. After hatching the polliwogs are very tiny and feed on plants. The polliwogs of the common toad are the smallest polliwogs in the country. They use gills to breathe, which they lose after their metamorphosis when they grow lungs. The toads also use their skin to absorb the oxygen in every stage of their lives. Once they change into small toads they transfer to land. The adult toads are fierce predators. They hunt not only insects, spiders and slugs, but also lizards, small snakes and mice! They are also equipped with an excellent defensive weapon, as there are venom glands on their skin. Because of those glands many predators leave them alone, although not all of them. The toads can also puff up and stand straight up on their legs in order to look bigger than they really are, which is a great defensive mechanism too. The common toads are immune to the venoms of wasps and of the common European viper, which allows them to feed on those as well.

The toads hibernate on land and not in water. They find hideouts in the ground, in abandoned lairs of rodents, under roots of trees or simply bury themselves. Sometimes if they have a chance they spend winter in basements of human houses. They always look for places that are warm in winter.